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Uited States NORTROPANE DERIVATIVES No Drawing. Application February 28, 1955, Serial No. 491,204

Claims priority, application Switzerland March 3, 1954 4 Claims. (Cl. 260-292) The present invention is concerned with nortropane derivatives. More particularly, it relates to nortropane derivatives which correspond to the formula:

CHzCH-CH:

N R HORQ CHP Hz wherein R1 stands for an alkoxyalkyl group, or a free or esterified carboxyl or hydroxyalkyl group, R2 stands for a carboxylic acid acyl group, and R3 stands for a lower alkyl group, and also to the salts and quaternary ammonium compound of said derivatives.

Carboxylic acids from which the new esters are derived include, for example, lower fatty acids, such as acetic acid, propionic acid, butyric acid, valeric acid, isovaleric acid, tiglic acid, etc.; aromatic carboxylic acids, such as benzoie acids, for example benzoic acid, alkoxy benzoic acids, methylene dioxy benzoic acids, etc.; and araliphatic acids, such for example as tropic acid, phenyl lactic acid, mandelic acid, fluorenyl-9-carboxylic acid, 9-hydroxyfluorenyl-9-carboxylic acid, benzilic acid, diphenyl acetic acid, phenyl-cyclohexyl acetic acid, phenyl-l-hydroxycyclohexyl acetic acid, xanthene-9 carboxylic acid, etc.

Especially suitable quaternary ammonium compounds are such as contain on the nitrogen atom as additional substituent a lower alkyl group, for example halogen methylates.

These nortropane derivatives of Formula I are severally advantageously prepared by condensing the appropriate 'y-ketoaldehyde corresponding to the formula OCH--( CH2 2CO--R1 ly activated hydrogen, and esterifying the so-obtained nortropine derivative with an acid of the formula wherein R2, as above, is acyl.

The said process may, for example, be carried out by condensing for instance 5-methoxylevulinaldehydeprepared by the hydrolysis of 2,5-dimethoxy-2-methoxymethyl-tetrahydrofurane with 0.1-norma1 sulfuric acidwithe. g. methylamine and acetone-dicarboxylic acid in atent bufiered aqueous solution at room temperature (e. g. 20-30 C.), and isolating the resultant l-methoxymethyltropinone by extraction with a water-immiscible solvent. Reduction of the l-methoxymethyl-tropinone yields the corresponding aminoalcohol, the tropine derivative re sulting if the reduction is carried out with catalytically activated hydrogen, and the pseudo-tropine derivative be ing obtained if nascent hydrogen is employed. Both de' rivatives, upon acylation, yield the corresponding acyl' derivatives.

Alternatively, the nortropinone derivatives of this invention can be synthesized by starting from a y-ketoaldehyde which contains an acylatable group in the 5-position, as for example from 5-hydroxy-levulinaldehyde-- obtained from 2,5-dimethoxy-2-hydroxymethyl-tetrahy5' drofurane-whereupon the product is a nortropinone derivative containing an acylatable group in the l-position, in the mentioned case a l-hydroxymethyl-nortropinone. This product can, prior to reduction to the notropine derivative, be acylated at the l-hydroxymethyl group to the 1-acyloxymethyl-nortropinone which, in turn, upon reduction and subsequent esterification yields a l-acyloxymethyl-3-acyloxy-nortropane derivative.

The acylation can be carried out in per se known manner, for example by treatment with an acid halide in the presence or absence of an acid-binding agent, by treat ment with an acid anhydride, or by alcoholysis, i. e. by the action of an acid ester on the alcohol-like tropane derivative under the catalytic influence of an alkali metal. The compounds used as starting materials can also be used in the form of their salts or quaternary ammonium compounds. I The new compounds are obtained in the form. of the ester bases, or salts or quaternary compounds thereof. From the salts, the free tertiary amines or ammonium compounds can be obtained in per se known manner. From the bases conversely, by reaction with acids which more especially are suitable for the formation of therapeutically useful salts, salts can be obtained, as for example those of the hydrohalic acids, nitric acid, phosphoric acid, thiocyanic acid, malic acid, methane sulphonic acid, hydroxyethane sulphonic acid, benzene or toluene sulphonic acids or other therapeutically active acids. Tertiary amine products can be quaternated in per se customary manner.

The compounds of the present invention-including the esters, salts and ammonium compounds-are solid crystalline compounds at room temperature (about 2()30 C.) and are pharmacologically very active. They are distinguished for example by their excellent action on the parasympathicus, and they are also useful in ther apy as spasmolytica. They have further utility as inter mediates in the preparation of other therapeutica.

Presently-preferred representative embodiments of the invention are set forth in the following illustrative examples. In such examples, the relationship between parts by weight and parts by volume is the same as that between grams and mililiters. The temperatures are indegrees centigrade. Percentages are by weight.

Example 1 4.1 parts by weight of diphenylacetic acid chloride in pyridine solution are added to 3 parts by weight of 1- hydroxymethyl-tropinone. After 6 hours, the pyridine is Patented May 29, 1956* sir-obtained 1=hydroxymethyl tropinone diph'e'nylac'etic acid ester is 160170/0;.06 mm. From the ester in alcohol solution and with the calculated quantity of picric acid, the picratemelting at 187 (with decomposition)-is prepared.

The 1-hydroxymethyl-tropinone, used as starting material, is prepared as follows:

40.5 parts by weight of 2,5-dimethoxy-2-hydroxymethyhtetrahydrofurane are kept at 70 for /2 hour in 390 parts by volume of 0.1-nrtnal sulfuric acid. The solution is then cooled to room temperature and added dropwise, in the course of /2 hour and while stirring, into a mixture of 75 parts by weight of acetone-dicarboxylic acid (neutralized in 440 parts by volume of water with 522 parts by weight of lime) and 240 parts by volume of a methylamine solution. The reaction mixture is additionally stirred for 3 hours and then allowed to stand for 2 hours, after which it is evaporated to dryness under reduced pressure at about The residue is taken up in normal sulfuric acid until the cloudy solution has an acid reaction to Congo red. The initially strong COzevolution can be carried to completion by heating on the water-bath, whereupon the liquid is cooledto room temperature and filtered from the precipitated calcium sulfate. The light brown filtrate is made strongly alkaline with aqueous caustic potash solution, saturated with sodium chloride, again filtered and extracted with ether for 3 days. Upon evaporating ofi the ether, 25 parts by Weight of crude base remain behind which, after distillation in high vacuum, are taken up in 100 parts by volume of alcohol, whereupon the calculated quantity oi alcoholic picric acid is added to the-hot alcoholic solution. Upon cooling, 46.5 parts by weight 'of picrate'are obtained. After several recrystallizations, the' thus-prepared 1-hydroxymethyl-tropinone picrate'r'ne lts at 191 (with decomposition).

. I CHE-C Example 2 l-hydroxymethyl-tropinone is 'acetylated by "treatment with acetic anhydride in pyridine, after the manner described in Example 1. The so obtaine'd l-acetoxymethyltropinone of the formula H2o=(|jH-t 3n2 I N-OH; C=O HzC- CH2 Hz-OCOCHa boils at 105-110 (0.04 mm.). Recrystallized from alcohol, the picrate melts at 165.

Example 3 4 is distilled in high vacuum. To the liquid distillate, there is added the calculated quantity of picric acid (2.4 parts by weight dissolved in 20 parts by volume of alcohol), whereupon the picrate of the said ester immediately crystallizes out. Recrystallized from acetone-water, the picrate melts at 183.

The 1-methoxymethyl-pseudotropine, used as starting material, can be prepared as follows:

14 parts by weight of 2,5-dimethoxy-Z-methoxymethyltetr'ahydrofur'ane are dissolved in 140 parts by volume of (ll-normal sulfuric acid and heated to for 15 minutes, complete hydrolysis of the acetal taking place. The hydrolysate is cooled and then neutralized with 1.5 parts by weight of calcium carbonate. The neutral aqueous aldehyde solution is added dropwise, in the course of /2 hour and while stirring, to a mixture of 24.4 parts by weight of acetone-dicarboxylic acid, 27 parts by weight of calcium carbonate, 156 parts by volume of water and 70 parts by volume of 40% methylamine. The reaction mixture is allowed to stand for 2 days at room temperature, whereupon it is carefully adjusted with 3-n0rmal hydrochloric acid until it is acid to Congo red. After the violent CO2- evolution has subsided, the reaction mixture is heated until gas development has practically ceased. The reaction mixture is made strongly alkaline with potassium carbonate and is then extracted with other for 3 days. From the ether extract, the base is shaken out with 3-norma1 hydrochloric acid, again liberated with solid potassium carbonate and taken up in. ether. After drying and evaporating ofi' the ether, there remains behind a weakly brownish-colored oil which can be purified by distillation under reduced pressure (boiling point=130/l2 mm) There is thus obtained the 1- methoxymethyl-tropinone of the formula boils at (air bath temperature) under a pressure of 0.04 mm. Hg.

Example 4 3 parts by weight of l-methoxymethyl-tropine are heated with 3.8 parts by weight of diphenylacetic acid chloride to fusion, after which" 15 parts 'by volume of pyridine are addedi Themixture is heated until dissolution is'achieved. After standing for 12 hours at room temperature, the pyridine is removed as completely as possible under reduced pressure, and the residue is taken up in water. The solution'is adjusted to acidity to Congo red and again extracted with ether. The aqueous solution is made strongly alkaline with potassium hydroxide and the milky emulsion is extracted with chloroform. The chloroform extract is] dried over magnesium sulfate, the chloroform evaporated OE, and the residue distilled at -140" in a high vacuum. The so-obtained colorless viscous oil is the diphenylac'etic acid ester of 1- methoxyniethyl-tropinez CH2-CH-CH2 OOC- H I l-H3 Q CH2 --$EH 3132-00113 The picrate-prepared with the equimolecular quantity of picric acid in hot alcohol and crystallizing out upon coolingmelts at 154.

The l-methoxymethyl-tropine, used as starting material, can be prepared as follows:

7 parts by weight of 1-methoxymethyl-tropinone are hydrogenated in 50 parts by volume of glacial acetic acid containing 0.700 parts by weight of platinum oxide. Precisely the calculated quantity of hydrogen is taken up within 4 hours, whereupon the hydrogenation ceases. The glacial acetic acid is removed under reduced pressure, the residue is taken up in the smallest possible quantity of water, and is then made strongly alkaline with potassium hydroxide and, in 10 portions, extracted with chloroform. The chloroform solution is dried over magnesium sulfate, evaporated, and the residue distilled in high vacuum. The colorless viscous oil (boiling point=about ll0/0.05 mm.) solidifies, after standing for several days, in the form of colorless prisms. The .so-obtained l-methoxymethyl-tropine of the formula melts at 70. Its picrate is obtained by reaction with the equimolecular quantity of picric acid in hot alcohol, followed by crystallization upon cooling. After recrystallization from alcohol, it melts at 143. In 50% aqueous acetone solution, it can be decomposed on an ion exchanger charged with chlorine ions. On evaporation of the solution, the crystalline hydrochloride is obtained.

Example 5 By replacing the l-rnethoxymethyl-tropine of Example 4 by the equivalent quantity of l-hydroxymethyl-tropine, and otherwise proceeding according to the said example, the corresponding diphenylacetic acid ester of l-hydroxymethyl-tropine is obtained.

The l-hydroxymethyl-tropine itself can be prepared as follows:

40.5 parts by weight of 2,5-dimethoxy-2-hydroxymethyl-tetrahydrofurane are maintained at 70 for /2 hour in 390 parts by volume of 0.1-normal sulfuric acid, after which the solution is cooled to room temperature and then added dropwise in the course of /2 hour to a mixture of 75 parts by weight of acetone-dicarboxylic acid (neutralized in 440 parts by volume of water with 52.2 parts by Weight of lime) and 240 parts by volume of 35% methyl-amine solution. The reaction mixture is further stirred for three hours and then allowed to stand for 2 days, whereupon it is evaporated to dryness at about 40 under reduced pressure. The residue it taken up in normahsulfuric acid until the turbid solution reacts acid to Congo red. The initially-vigorous COzevolution is completed by heating on the water bath, whereupon the liquid is cooled to room temperature and filtered from precipitated calcium sulfate. The light brown filtrate .is rendered strongly alkaline with caustic potash solution, saturated with sodium chloride, again filtered and extracted with ether for 3 days. On evaporation of the ether, parts by weight of crude base remain, which after distillation under high vacuum is taken up in 100 parts by volume of alcohol, and the hot solution treated with the calculated quantity of alcoholic picric acid. 011' cooling, 46.5 parts by weight of picrate crystallize; After repeated recrystallization, the resulting picrate of the 1-hydroxymethyl-tropinone of the formula:

H -OH melts at 191 (with decomposition). 0.1256 part by weight of 1-hydroxymethyl-tropinone is hydrogenated in 10 parts by volume of glacial acetic acid in the presence of 0.500 part by weight of platinum oxide in a microhydrogenation apparatus. The ketone takes up exactly the calculated quantity of hydrogen within 20 minutes. The glacial acetic acid is removed under reduced pressure, and the residue taken up in a few drops of water and rendered alkaline with a few drops of potassium hydroxide solution. After extraction with chloroform and drying of the extract over magnesium sulfate, the solvent is removed and the base distilled under high vacuum. The distillate solidifies in the form of well-defined leaf lets, which in the air take up water and deliquesce. 0.500 part by weight of the so-obtained l-hydroxymethyltropine of the formula:

oHioH--orn on bHr-OH are treated hot with the calculated quantity of alcoholic picric acid. The picrate crystallizes immediately as welldefined prisms which, after recrystallization from isopropyl alcohol, give no clear melt up to 270. picrate decomposes gradually with dark coloration above 250 C.

Example 6 and distills at -l10 (air bath temperature) under 0.04 mm. pressure. The picrate of l-acetoxymethyltropinone of the formula:

can be recrystallized from alcohol and melts at 165. The ketone can be converted by catalytic reduction with platinum oxide in glacial acetic acid into the l-acetoxymethyltropine of the formula:

the picrate of which, recrystallized from alcohol, melts at Example 7 By replacing the l-methoxymethyl-tropine of Example 4 by the equivalent quantity of l-carbomethoxy-tropine, and otherwise proceeding according to the said example, the corresponding diphenylacetic acid ester of l-carbomethoxy-tropine is obtained.

The

The, .l-carb omethoxy-t ropine itself can be prepared as follows:

115 parts byweight o'f 2,5 dimethoxy 2 carbomethoxytetrahydrofuranearehydrolyzed with 87 parts by volume of (ll-normal sulfuric acid and the solution neutralized with 1.3 parts by weight of calcium carbonate. The neutral hydrolysate is added dropwise with stirring within half an hour to a mixture of 18.1 parts by weight of acetone-dicarboxylic acid, parts by weight of lime, 120 parts by volume of waterand '50 parts by volume of 40% methylamine. After 2 days, the weakly light brown solution is rendered acid to Congo red with sulfuric acid and heateduntil foaming ceases. The precipitated calcium sulfate is separated by centrifuging, the weakly brown solution extracted by shaking with ether and then rendered strongly alkaline with excess of baryta solution. The solution is centrifuged from barium sulfate and considerably concentrated under reduced pressure at until the methylamine is removed and the solution is free from odor. The solution, alkaline with baryta, is carefully practically completely neutralized with dilute sulfuric acid and then all sulfate ions precipitated by addition of baryta. The neutral solution is again freed from barium sulfate by centrifuging and evaporated to dryness under reduced pressure at 60. A brownish colored, crystalline product remains which is very easily soluble in water but difiicultly soluble in alcohol. From alcohol-water, 6.3 parts by weight of colorless crystals separate out. l-carboxytropinone crystallizes with /2 molecule of water of crystallization. Melting point =l64 (with decomposition). 5 parts by weight of carboxy-tropinone are dissolved in 150 parts by volume of HCl-saturated methanol, the whole heated to boiling for half an hour and then allowed to stand overnight at room temperature. The methanol is removed under reduced pressure and the colorless glassy residue taken up in a little water and, under ether, rendered alkaline with sodium bicarbonate. The aqueous layer is extracted five times with 50 parts by volume of ether and the dried ether extract evaporated. The ester of the formula:

CH;CHCB.

Af-CH (i=0 cure on:

o 0 0 CH3 OOCHs Example 8 5.2 parts by weight of 1-acetoxymethyl-ttpp leereedissolved in 30 parts by volume of pyridine, and then 15 parts by weight of phenyl-cyclohexyl-acetic acid chloride are added. After l2' hours, the reaction mixture is heated for 1 hour on the water bath, then freed as. far as possible from pyridine under reduced pressure. The resultant viscous residue is stirred with parts by volume of 1- normal hydrochloric acid. The separated excess phenylcyclohexyl-acetic acid is removed by shaking out several times with ether. The acid aqueous solution is then rendered alkaline with aqueous caustic potash solution, and the separated ester base is taken up in chloroform. The crude base can be purified by chromatographing on aluminum oxide with benzene and distilling in high vacuum. The sax-obtained l-acetoxymethyl-tropine-phenyl-cyclohexyl acetic acid ester is a colorless viscous liquid, from which the iodomethylate can be obtained with the aid :of methyl iodide. The chloromethylate can be prepared by reacting the iodomethylate, in aqueous solution, with fresh ly precipitated AgCl. The hydrochloride of the pure ester base can not be crystallized.

The acylating agents used in the foregoing examples can be replaced by acylating derived from any of the other carboxylic acids, hereinbefore enumerated.

The quaternating agentsemployed in the examples may be replaced by any other conventional quaternating agent, alkyl halide or other alkyl ester of an inorganic acid, etc.

Theester bases of-the examples or the quaternary ammonium compounds can be converted to the salts of any of the hercinbefore enumerated salt-forming acids.

Having thus disclosed the invention, what is claimed is:

l. A compound selected from the group consisting of nortropanes which correspond to the formula therapeutically-useful salts thereof with acids, and the quaternary ammonium compounds thereof, wherein R1 stands for a member selectedfrom the group consistingof carbomethoxy, methoxymethyl, acetoxymethyl and diphenyl-acetoxy-methyl, R2 stands for a member selected from the group consisting of phenyl, benzhydryl and wcyclohexyl-benzyl, and R3 stands for lower alkyl.

2. The i-methoxymethyl-pseudotropine-benzoic acid ester.

3. The l-methoxymethyl-tropine-diphenylacetic acid ester.

4. The l-acetoxymethyl tropine-phenyl cyclohexylacetic acid ester.

No references cited. 

1. A COMPOUND SELECTED FROM THE GROUP CONSISTING OF NORTROPANES WHICH CORRESPOND TO THE FORMULA 